This invention relates to pretreating of the surfaces of electrically conductive materials in general and more particularly to a pretreatment method which can be used when preparing materials for electroplating in a aprotic, oxygen- and water-free organoaluminum electrolytic media.
Because of its ductility, freedom of pores, corrosion resistance and ability to be anodized, aluminum which is electrodeposited from an aprotic, oxygen- and water-free, organoaluminum electrolytic media has been found to be particularly well suited for many technical purposes. The metal deposited using this electrolyte is extremely pure and adheres very well to bare surfaces. However, these surfaces must be absolutely free of oxides and hydroxides. The deposition of highly adhering, homogeneous coatings which will remain free of blisters is not possible on surfaces containing oxides, hydroxides or moisture. In addition, the presence of such on the surfaces is also detrimental to the life of the electrolyte since they reduce its conductivity and its life.
It is been found that these problems can be avoided if bright work piece surfaces which are free of cover layers are used in the process. Thus, it is the object of the present invention to provide a method of pretreating materials which are to undergo this electroplating process to facilitate providing the material in a condition where its surfaces do not contain oxides, hydroxides and mositure.